An operating budget refers to a financial plan that outlines the expected revenue and expenses of a business operation. There are several synonyms for this term, including an expense budget, financial plan, financial forecast, profit and loss budget, and spending plan. These synonyms are used interchangeably to describe the same concept. An expense budget typically refers to the planned expenses while a financial forecast outlines the expected revenue and expenses over a certain period. A spending plan is a detailed budget used to allocate funds for specific activities. In the end, the term used will depend on the context of the situation.